EP1462811A1 - Elektrooptischer Spannungssensor für hohe Spannungen - Google Patents
Elektrooptischer Spannungssensor für hohe Spannungen Download PDFInfo
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- EP1462811A1 EP1462811A1 EP03405271A EP03405271A EP1462811A1 EP 1462811 A1 EP1462811 A1 EP 1462811A1 EP 03405271 A EP03405271 A EP 03405271A EP 03405271 A EP03405271 A EP 03405271A EP 1462811 A1 EP1462811 A1 EP 1462811A1
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- Prior art keywords
- electro
- optically active
- layer
- active layer
- layers
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/24—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using light-modulating devices
- G01R15/241—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using light-modulating devices using electro-optical modulators, e.g. electro-absorption
- G01R15/242—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using light-modulating devices using electro-optical modulators, e.g. electro-absorption based on the Pockels effect, i.e. linear electro-optic effect
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/24—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using light-modulating devices
- G01R15/247—Details of the circuitry or construction of devices covered by G01R15/241 - G01R15/246
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/0084—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring voltage only
Definitions
- the invention relates to the field of electro-optical voltage sensor technology. It relates to an electro-optical voltage sensor according to the preamble of claim 1 and a method for electro-optical voltage measurement according to the preamble of the claim 14th
- Such a voltage sensor is, for example, from JC Santos, K. Hikada, "New Multi-Segment Pockels Device for High-Voltage Measurement", Proc. ICEE '96 (International Conference on Electrical Engineering), p. 1366-1370 known.
- the sensor described by Santos and Hikada comprises a plurality of disks made of crystalline BGO (Bi 4 Ge 3 O 12 ), which are arranged at a distance from one another between two electrodes, to which the voltage V to be measured is applied. Cylindrical dielectric spacers are used to space the BGO disks, which are arranged in a row at regular intervals between the electrodes. The spaces between the BGO panes and the area around the sensor are filled with SF 6 .
- the BGO disks are irradiated with a light beam, the state of polarization of which due to the Pockels effect (linear electro-optical Effect) depending on the voltage V changes.
- two orthogonally polarized light waves are coupled into the BGO crystals, which due to the electro-optical activity to each other one of experience the voltage V dependent phase shift. This phase shift is detected and serves as a voltage signal from the sensor.
- the voltage signal is clear.
- the corresponding maximum uniquely determinable voltage is the half-wave voltage V ⁇ .
- the sensor is normally designed so that the clear range corresponds to a phase shift of -90 ° to + 90 °.
- the voltage is then in the range -V ⁇ / 2 to V ⁇ / 2.
- this half-wave voltage V ⁇ (or V ⁇ / 2) is quickly exceeded in conventional sensors which have a single electro-optically active crystal between the electrodes.
- the arrangement of individual thin slices of electro-optically active material proposed by Santos and Hikada can significantly reduce the overall phase shift detected.
- a voltage sensor is to be created which allows a clear measurement of high voltages.
- An electro-optical voltage sensor with the features solves this task of claim 1 and a corresponding measurement method with the Features of claim 14.
- a voltage sensor has two spaced electrodes between which a voltage V to be measured is present. Through the applied voltage V, an electric field E is generated. Between Electrodes are at least a first electro-optically active layer and at least one second electro-optically active layer along a light path arranged one behind the other. Each of the two electro-optically active layers has at least two axes of birefringence, each of the A refractive index is assigned to each axis. That means that linearly polarized Light whose direction of polarization along such an axis of Birefringence is aligned, the corresponding refractive index "Sees".
- the voltage sensor according to the invention is characterized in that an orientation defined by the corresponding axes of birefringence relative to the at least one first electro-optically active layer to the light path and the electric field E and one by the corresponding Axes of birefringence defined orientation of at least a second electro-optically active layer relative to the light path and the electric field E are chosen such that the influence on the phase and / or the polarization state of the light in the first layer of the Influencing the phase and / or the polarization state of the light in counteracting the second layer.
- linearly polarized light at 45 ° to two axes of Birefringence coupled into the first electro-optically active layer see above that the light is in the form of two in the electro-optically active layers propagates orthogonally polarized light waves as a voltage signal a mutual phase shift of these waves or a Polarization state of the light emerging from the layers measured become.
- becomes a linearly polarized light wave coupled at 0 ° or 90 ° into the first electro-optically active layer see above that the light in both electro-optically active layers is in the form of a single linearly polarized light wave propagates as a voltage signal a phase of this wave can be measured.
- the crystallographic orientation of the electro-optically active layers is chosen such that an enlarged half-wave voltage V ⁇ of the sensor is generated.
- a larger half-wave voltage V ⁇ is achieved in the sense that the half-wave voltage V ⁇ of the sensor is greater than a half-wave voltage of a similar sensor, which differs from the sensor only in that the at least one second layer is not electro-optically active.
- a half-wave voltage V ⁇ of the sensor can be defined by means of the refractive index changes for a light beam that shines through the electro-optically active layers. If a light beam is passed through the sensor, or more precisely: the electro-optically active layers, in a suitable manner, the phase and / or the state of polarization of the light beam changes as a function of the electrical field.
- a voltage signal from the sensor can be obtained from such a change in the phase and / or the polarization state of the light. However, due to the wave nature of the light, such a signal is periodic, so that above a voltage characteristic of the sensor, the half-wave voltage V ⁇ , the voltage signal is ambiguous.
- a half-wave voltage V ⁇ can be defined by means of the refractive index changes and the light beam, a basic functioning of the voltage sensor is ensured.
- Various conditions known to the person skilled in the art for example with regard to the electric field E, the light (light path, polarization) and with regard to their mutual arrangement, are thus fulfilled.
- a light beam is radiated into the electro-optically active layers in the sensor, which is influenced in the electro-optically active layers as a function of the electric field, and which is then detected.
- a voltage signal is then obtained from the light detected after passing through the layers.
- the influence that the light experiences in the at least one first electro-optically active layer is partially reversed in the at least one second electro-optically active layer, that is to say partially compensated.
- a voltage signal of the same size is only reached at a higher voltage V, so that a larger half-wave voltage V ⁇ results.
- the layers are along this same coordinate shone through with light.
- the crystalline BGO layers are like this oriented to each other that in the preferred case the [001] directions of the crystals are aligned antiparallel to each other, while the [010] directions parallel and the [100] directions anti-parallel (or, alternatively, the [010] directions anti-parallel and the [100] directions parallel) to each other are aligned.
- the electro-optically induced influences on the light in the first and in the Pick up the second layer exactly, as they are not only opposite, but would also be the same size.
- An electro-optically active material (electro-optical crystal) has two for an axis of birefringence relevant to the crystal interrogating light beam (depending on the electrode geometry, the light path and the Crystal geometries). These axes are (in pairs) perpendicular to each other aligned.
- An electric field generated in a suitable manner leads to a Change in birefringence with respect to these axes. It means that the refractive index assigned to it for at least one of these axes depending on the field E changes.
- a mutual according to the invention Orientation of the electro-optically active layers can be done well via the mutual relative orientation of these two axes of birefringence defined become.
- the mutual orientation of the electro-optically active layers is such chosen that the effect that the electric field has on the least two electro-optically active layers scanning light beam in the first electro-optically active layer, in part due to the effect that the electric field on the at least two electro-optically active layers has a scanning light beam in the second electro-optically active layer, is compensated or canceled.
- the omens are worded differently of the effects mentioned in the two electro-optically active layers opposed. Because the electro-optical effect always shifts the phase of light is always a forerunner of such Effect definable.
- a sensor according to the invention has the advantage that it can also be used with large sensors Voltages still delivers unique voltage signals. So are safe Measurements in the high voltage range (typically 100 kV to 1000 kV) possible. In addition, it is possible to implement such a sensor that has only very low reflection losses.
- the two layers have the same Crystal symmetry, and the layers are oriented such that the crystalline Orientation of the second layer results from the crystalline orientation the first layer by rotating the first layer by 180 ° one of the axes of the birefringence of the first layer results. This allows to achieve a relatively simple interpretation of the voltage signals.
- the layers can advantageously consist of the same material. reflections at interfaces between different layers are minimized.
- the layers consist of the same material and are arranged with said crystalline orientation (rotated against one another by a birefringence axis by 180 °) and have effective layer thicknesses ⁇ 1 , ⁇ 2 which are different from one another.
- the half-wave voltage V ⁇ of the sensor can be selected via the difference in the layer thicknesses ⁇ 1 , ⁇ 2 .
- pairs arranged in pairs are particularly advantageous arranged first and second layers. This can make an accurate and insensitive to external disturbances in the field distribution Voltage measurement can be achieved.
- the plurality of first and second arranged in pairs electro-optically active layers arranged between the electrodes in this way be that a deviation of the determined by means of the voltage sensor Voltage of the voltage V to be measured is minimal.
- a deviation the voltage signal of the sensor, that is to say by means of the voltage sensor certain voltage, of the voltage V to be measured is then below a predefinable limit.
- Such an arrangement of the layers is can be determined, for example, using approximate calculations or simulations. Particularly precise measurements and great insensitivity can be made against external disturbances of the electrical field, for example due to of rain or snow near the sensor, and against cross fields, for example due to adjacent electrical phases near the sensor become.
- a further advantageous embodiment is characterized in that the layers are arranged in a stack between the electrodes, wherein the first layer and the last layer in the stack, each with one of the two Electrodes is in contact.
- the stack can advantageously essentially be cylindrical.
- the layers preferably form a sensor rod. A mechanically stable structure with a large dielectric Strength is realized in this way.
- the sensor can also be one or more non-electro-optically active Spacer layers can be arranged between the electrodes. Thereby further degrees of freedom are obtained for the design of the sensor.
- a particularly advantageous embodiment is characterized in that the layers consist of crystalline BGO (bismuth germanium oxide, Bi 4 Ge 3 O 12 ), the BGO in the first and second layers with its [001] direction parallel or antiparallel to Direction of propagation of the light is oriented, and wherein the direction of propagation of the light extends essentially along the electric field E generated by the voltage V.
- the [110] directions of the crystals are advantageously oriented essentially parallel or antiparallel.
- the electrodes together with the between the Layers arranged in electrodes are cast in silicone.
- Silicone coating is a sensor with very small dimensions and small Weight producible, which nevertheless has sufficient electrical Isolation. Expensive, large, heavy insulation pipes, typically made of glass fiber reinforced plastic can be avoided. The minor Weight and the small dimensions allow the sensor to be used in places or in layers, on or in which conventionally isolated sensors cannot be used. For example, hanging on a high-voltage cable Installation part.
- the sensor is advantageously designed for measuring voltages V which are less than or equal to a maximum voltage V max to be measured, the number and orientation of the first and second layers and their effective layer thicknesses and the materials from which the layers are made chosen in this way are that V max is less than or equal to the half-wave voltage V ⁇ of the sensor.
- the inventive method measurement of an electrical voltage V wherein the voltage V is present between two electrodes spaced apart from one another and generates an electric field E, wherein at least one first electro-optically active layer is arranged between the electrodes, which layer is traversed by a light beam, the phase and / or state of polarization of which is caused by the electric field E in the first layer is influenced, and wherein at least a second electro-optically active layer is arranged between the electrodes, which is traversed by the light beam, the phase and / or polarization state of which is influenced by the electric field in the second layer, characterized in that the influence experienced by the light beam in the at least one first layer is partially canceled by the influence experienced by the light beam in the at least one second layer.
- Fig. 1 shows a highly schematic of a voltage sensor according to the invention.
- Two layers 1a, 2a made of electro-optically active material, advantageously BGO layers, are arranged between two electrodes 3, 4, between which a voltage V to be measured is present.
- the voltage V generates an electric field E.
- the layer thickness of the first layer 1a is ⁇ 1
- the layer thickness of the second layer 1a is ⁇ 2 .
- a light beam 5 shines through both layers 1a, 2a. Details of the properties of the light 5, its generation and detection can be found in the unpublished EP application mentioned.
- the two electro-optically active layers 1a, 2a are designed as cylindrical elements which together form a sensor rod which extends from one electrode 3 to the other electrode 4.
- the total length of the sensor rod here corresponds to an electrode spacing L.
- ⁇ 1 + ⁇ 2 L applies here.
- the crystalline orientation of the two BGO layers 1a, 2a is illustrated to the right of the sensor.
- the [001] directions (along which the light 5 propagates here and which are equivalent to [010] and [100] due to the crystal symmetry) are aligned antiparallel to each other and point along one through the electrodes 3, 4 (or their Distance) predetermined coordinate, along which the axis of the sensor rod is also aligned.
- a 1.1 and a 1.2 two axes of the birefringence of the first electro-optically active layer 1a which are relevant for the sensor are designated.
- a 2.1 and a 2.2 denote two axes of birefringence of the second electro-optically active layer 2a which are relevant for the sensor.
- these axes of birefringence correspond to the [110] - and [ 1 10] crystal directions.
- the relative crystalline orientation of the two layers 1 a, 2 a is such that the crystalline orientation of the second layer 2 a results from the crystalline orientation of the first layer 1 a by rotating the first layer 1 a by 180 ° about one of the axes of birefringence a 1 , 1 or a 1,2 (corresponding to [110] or [ 1 10]) results.
- the corresponding axes a 1.1 and a 2.1 of the first and second layers are aligned parallel to one another, as are the corresponding axes a 1.2 and a 2.2 .
- the crystal directions parallel to the axes are aligned antiparallel to each other, in the second case (a 1,2 and a 2,2 ) parallel.
- axes relevant to the sensor are referred to as "axes relevant to the sensor" of the birefringence because, depending on the electric field E, there are in each of the layers at least one refractive index n i, 1 and n i, 2 assigned to one of the axes changes.
- the light beam 5 which shines through the layers 1a, 2a experiences an electro-optically induced influence. This influence is generally detected as a changed polarization state or as a changed phase position of the light 5.
- crystal directions are a pair of birefringence axes relevant for the sensor depends on the crystal symmetry and the direction the light propagation and the direction of the electric field E.
- On functional sensor has such a pair of axes of birefringence in at least two, advantageously all electro-optically active layers on.
- the influences that the light 5 experiences in the first and in the second layer are partially compensated for.
- ⁇ k 1 ⁇ E ⁇ ( ⁇ 1 - ⁇ 2 ) 2 ⁇ / ⁇ .
- the size of the total phase shift ⁇ can be reduced by choosing the layer thicknesses ⁇ 1 , ⁇ 2 compared to the individual phase shifts ⁇ 1 , ⁇ 2 in the layers 1a, 2a or their sum.
- the total phase shift ⁇ as a voltage signal can thus be scaled down.
- FIG. 2 shows a particularly advantageous embodiment of the invention.
- a single pair of two electro-optically active layers 1a, 2a is arranged between the electrodes 3, 4, but a plurality, namely four, first and second electro-optically active layers 1a, 1b, 1c, 1d, 2a, 2b, 2c, 2d ,
- These are advantageously arranged in pairs, so that first and second layers in the light path 5 are always arranged one behind the other and even adjoin one another here.
- the sensor rod thus consists of a stack of alternately arranged first and second layers.
- the crystalline orientation of the layers 1a, 1b, 1c, 1d, 2a, 2b, 2c, 2d is advantageously chosen, as indicated in FIG. 1.
- the thick arrows to the left of the sensor rod illustrate the [001] direction.
- the corresponding axes of the birefringence of different pairs are aligned either parallel or antiparallel to each other.
- the layer thicknesses ⁇ 1 , ⁇ 2 are chosen to be the same for all first and second layers.
- the electrodes 3, 4 have field control electrodes 3 a, 4 a and voltage leads 3 c, 4 c.
- first and second electro-optically active layers 1a, 1b, 1c, 1d, 2a, 2b, 2c, 2d in pairs, a more accurate voltage measurement and a significantly reduced sensitivity to external disturbances in the field distribution can be achieved.
- Each layer can have its own layer thickness ( ⁇ 1 (a) , ⁇ 2 (a) , ⁇ 1 (b) , ⁇ 2 (b) ...), which can be different from the other layer thicknesses.
- the cited unpublished EP application describes ways to optimize the arrangement in such a way that the deviation of the measured voltage from the voltage V to be measured is minimized. Details of this are given in the US Pat. No. 4,939,447 and in the publication Optics Letters 14, 290, 1989. The disclosure content of these texts is hereby expressly included in the description.
- Each pair of layers supplies a partial voltage signal, which is a measure of that prevailing electric field in the area of the respective pair of layers. All pairs are advantageously scanned with a single light beam 5.
- Fig. 3 shows schematically a voltage sensor, in particular the optical components of the sensor are shown.
- the reference numbers can be found in the list of reference symbols. Further details are the above Unpublished EP application: The shown there in Fig. 1 Except for the sensor rod, the sensor is identical to that shown in Fig. 3 shown.
- the sensor rod of the sensor shown in FIG. 3 comprises three pairs of first and second layers 1a, 1b, 1c, 2a, 2b, 2c.
- the thick arrows to the right of the sensor rod illustrate the crystalline orientation of the layers, analogous to Figs. 1 and 2.
- Not all of the first layers 1a, 1b, 1c and not all of the second layers 2a, 2b, 2c have the same layer thicknesses.
- the middle pair of layers 1b, 2b has layer thicknesses ⁇ 1 'and ⁇ 2 ', which are twice as large as the corresponding layer thicknesses ⁇ 1 and ⁇ 2 of the other layers 1a, 1c, 2a, 2c.
- That for the phase shift experienced by light 5 in a pair of layers or polarization change relevant electrical field is the field at Location of the pair of layers.
- the total thickness of each pair of layers can be in Principle can be chosen freely, so that the voltage V to be measured by a Sum of partial signals, which are in principle freely selectable locations of the Layer pairs are generated, is approximated.
- One for each Layer pair practically free and individually selectable layer thickness difference between the first and second layers of the respective pair of layers the sum of partial signals mentioned can be weighted almost arbitrarily. This allows a sensor structure to be optimized for a given field profile so that accurate measurement results can be achieved.
- FIG. 4 shows a further advantageous embodiment of the sensor. She is characterized in that the essential parts, in particular the Field control electrodes 3a, 4a and the sensor rod, coated with silicone 15 are. Further details on this embodiment are the aforementioned unpublished EP application can be seen, the figure 8 except for the other designed sensor rod of FIG. 4 corresponds.
- a sensor rod is of course appropriate of the present invention.
- the light path 5 can also optical means such as reflection means and optical fibers have, by means of which the light before, between or after passing through is arranged between the electrodes arranged layers.
- the light beam 5 and the electric field E advantageously run parallel to a high symmetry axis of the crystal.
- the birefringence axes a i, 1 , a i, 2 thus advantageously correspond to axes of high symmetry of the crystal.
- the light beam 5 and the electric field E preferably run along the [100] direction or an equivalent crystal direction ([010], [001]). This has the advantage that field components that are orthogonal to this direction have no influence on the polarization state or the phase of the light 5 (low sensitivity to interference).
- the axes of high symmetry of the crystal and the light path 5 and the electric field E are, as described above, preferably aligned essentially parallel or perpendicular to one another.
- the high symmetry axes of the electro-optically active layers can include an angle different from 0 ° and a multiple of 90 ° with the direction of light propagation and / or with the direction of the electric field.
- the angle enclosed by the direction of light propagation and the direction of the electric field can also differ from 0 ° and a multiple of 90 °. Details on the dependence of the electro-optical effect in any crystal on the field and light propagation direction can be found, for example, in the book by JF Nye: “Physical Properties of Crystals", Oxford University Press, 1957 or other works on crystal optics. It is thus possible for a person skilled in the art to implement a voltage sensor according to the invention with a wide variety of angles.
- crystalline orientation generally means the orientation of the electro-optically active layers defined by the relevant axes of birefringence a i, 1 , a i, 2 .
- electro-optically active materials are always of a crystalline structure.
- non-crystalline materials such as gases, liquids, non-crystalline solids
- an electro-optical activity of the type considered here is present or can be induced, these materials then having no crystal axes but axes of birefringence.
- non-electro-optically active spacer layers can also be used (corresponding to the "distance medium" in the unpublished EP application) can be arranged in the sensor rod, which then has a corresponding Contribute to temperature compensation.
- quartz glass is suitable for such a spacer layer.
- an E-field dependent change understood a birefringence in a mostly crystalline material.
- the effect can be linear (Pockels effect) or other dependencies on the electric field strength, for example a square, exhibit.
- Birefringence means that there are two orthogonal to each other Axes (of birefringence) two different refractive indices which are "experienced" by light waves along their polarization is aligned with such an axis.
- a change in birefringence can mean that only one assigned to a birefringence axis Refractive index changes or that two such refractive indices differ change, the latter by increasing the one at simultaneous lowering of the other refractive index or by a different degree of refractive index change of the same sign can.
- the longitudinal Pockels effect was always used in the exemplary embodiments (Direction of light propagation essentially parallel to the electric field) exploited. But in principle it is also possible to use the transverse Pockels effect (Direction of light propagation essentially perpendicular to the electrical Field) and depending on the type of electro-optically active material and its crystalline orientation to construct a corresponding sensor. Basically, the arrangement of the electro-optically active Layers between the electrodes 3, 4 can be any. In the longitudinal Pockels effect is advantageously the one chosen in the exemplary embodiments Arrangement selected so that the light path 5 parallel to the electric field E runs, and that the electro-optically active layers along the electrode spacing (along the electric field E) arranged one behind the other are.
- the layers can also be in of this type can be arranged, in which case optical means such as mirrors or Glass fibers are shown, by means of which the light beam 5 after exit can be coupled from a first layer 1a into a second layer 2a, because the light beam 5 is essentially perpendicular within the layers spreads to the sensor rod.
- the two layers be oriented in exactly the same way relative to each other or even the same Be crystal, of course their relative orientation to light path 5 (more precisely: to that specified by the light path 5 in the respective layer Direction of light propagation) is different.
- first and a second layer are a first and a second layer (possibly several each arranged in pairs with respect to the electrode spacing, so that no optical means are necessary to get the light 5 from the first to lead to the second shift. In this case, this can be done in pairs of layers by means of several light beams 5.
- the transverse Pockels effect Sensor has one based on the transverse Pockels effect Sensor, however, has a large cross sensitivity (influencing through external fields that are not in the same orientation as that measuring field).
- the effective distance L of the electrodes 3, 4 is in the exemplary embodiments of the figures the geometric length that the light 5 between the electrodes 3.4 covered. L thus corresponds to the geometric minimum distance between the electrodes 3,4.
- the effective distance L can vary, for example then differentiate from the geometric spacing of the electrodes, when the field electrodes 3a, 4a are bent in the radial direction Have profile so that the minimum geometric distance between the Field electrodes 3a, 4a is smaller in the radial outer region than in the radial one Inner area where the transparent parts of the electrodes 3, 4 are arranged are. Also in the case of electrodes not aligned parallel to each other 3.4 would be the geometric minimum distance between the electrodes generally do not correspond to the effective distance L of the electrodes 3, 4.
- the effective distance L of the electrodes 3, 4 can be from the light guide depend.
- the effective layer thicknesses are correct in the exemplary embodiments with geometric thickness of the individual layers of the match. For example in In case of uneven layer surfaces or if the layers are not plane-parallel are formed, a geometric layer thickness is not easy Are defined. That is why the term "effective layer thickness" was introduced. Further explanations can be found in the unpublished EP application mentioned be removed.
- first and second layers are advantageous from one Extend electrode 3 to the other electrode 4, others can Layers (also gas, liquids, vacuum) between the layers or be arranged between the layers and one or both electrodes.
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Abstract
Description
- massgeblicher elektrooptischer Koeffizient (k),
- Dielektrizitätskonstante (ε) und
- thermischer Ausdehnungskoeffizient (α)
wobei die Spannung V zwischen zwei voneinander beanstandet angeordneten Elektroden anliegt und ein elektrisches Feld E erzeugt, wobei zwischen den Elektroden mindestens eine erste elektrooptisch aktive Schicht angeordnet wird, welche von einem Lichtstrahl durchlaufen wird, dessen Phase und/oder Polarisationszustand durch das elektrische Feld E in der ersten Schicht beeinflusst wird, und wobei zwischen den Elektroden mindestens eine zweite elektrooptisch aktive Schicht angeordnet wird, welche von dem Lichtstrahl durchlaufen wird, dessen Phase und/oder Polarisationszustand durch das elektrische Feld in der zweiten Schicht beeinflusst wird, kennzeichnet sich dadurch, dass die von dem Lichtstrahl in der mindestens einen ersten Schicht erfahrene Beeinflussung von der von dem Lichtstrahl in der mindestens einen zweiten Schicht erfahrenen Beeinflussung teilweise aufgehoben wird.
- Fig. 1
- einen erfindungsgemässen Spannungssensor, stark schematisiert, mit angedeuteten Kristallorientierungen;
- Fig. 2
- einen erfindungsgemässen Spannungssensor mit vier Paaren von ersten und zweiten elektrooptisch aktiven Schichten, schematisch;
- Fig. 3
- einen erfindungsgemässen Spannungssensor in Transmissionsgeometrie, mit drei Paaren von ersten und zweiten elektrooptisch aktiven Schichten, schematisch;
- Fig. 4
- einen erfindungsgemässen Spannungssensor mit Silikonummantelung, schematisch.
- 1a, 1b,...
- erste elektrooptisch aktive Schicht, erster BGO-Kristall
- 2a,2b,...
- zweite elektrooptisch aktive Schicht, zweiter BGO-Kristall
- 3
- Elektrode
- 3a
- Feldsteuerungselektrode
- 3b
- Spannungszuführung
- 4
- Elektrode
- 4a
- Feldsteuerungselektrode
- 4b
- Spannungszuführung
- 5
- Licht, Lichtstrahl, Lichtweg
- 6a
- optische Zuführungsfaser
- 6b
- optische Rückführungsfaser
- 7a,7b
- Kollimatorlinse
- 8a,8b
- Polarisator
- 9
- λ/4-Element
- 15
- Silikon
- 16
- Lamellen (Beschirmung)
- 17
- Koronaring
- ai,1,ai,2
- Achsen der Doppelbrechung der i-ten elektrooptisch aktiven Schicht
- k1
- massgeblicher elektrooptischer Koeffizient des Materials einer ersten Schicht
- k2
- massgeblicher elektrooptischer Koeffizient des Materials einer zweiten Schicht
- ni,1,ni,2
- Brechungsindex, einer Achse der Doppelbrechung der i-ten elekt- rooptisch aktiven Schicht zugeordnet
- E
- elektrisches Feld, Feldlinie
- L
- effektiver Elektrodenabstand
- V
- zu messende elektrische Spannung
- Vπ
- Halbwellenspannung
- δ1,δ1'
- effektive Schichtdicke einer ersten elektrooptisch aktiven Schicht
- δ2,δ2"
- effektive Schichtdicke einer zweiten elektrooptisch aktiven Schicht
- Γ,Γ1,Γ2
- Phasenverschiebung
Claims (14)
- Elektrooptischer Spannungssensor zur Messung einer elektrischen Spannung V, wobei die Spannung V zwischen zwei beabstandet angeordneten Elektroden (3,4) anliegt und ein elektrisches Feld E erzeugt, wobei zwischen den Elektroden (3,4) mindestens eine erste elektrooptisch aktive Schicht (1a,1b,1c,1d) und mindestens eine zweite elektrooptisch aktive Schicht (2a,2b,2c,2d) entlang eines Lichtweges (5) hintereinander angeordnet sind, wobei jede dieser Schichten (1a,1b,1c,1d; 2a,2b,2c,2d) zwei Achsen der Doppelbrechung ai,1,ai,2 aufweist, denen jeweils ein Brechungsindex ni,1,ni,2 zugeordnet ist, und wobei in jeder dieser Schichten (1a,1b,1c,1d; 2a,2b,2c,2d) mindestens jeweils einer dieser Brechungsindices, ni,1, durch das elektrische Feld E veränderbar ist, wodurch in jeder dieser Schichten (1a,1b,1c,1d; 2a,2b,2c,2d) eine Phase und/oder ein Polarisationszustand des Lichtes (5) beinflussbar ist, wobei der Index i = 1,2 die erste beziehungsweise zweite elektrooptisch aktive Schicht indiziert,
dadurch gekennzeichnet, dass
eine durch die Achsen der Doppelbrechung a1,1,a1,2 definierte Orientierung der mindestens einen ersten elektrooptisch aktiven Schicht (1a,1b,1c,1d) relativ zu dem Lichtweg (5) und dem elektrischen Feld E und eine durch die Achsen der Doppelbrechung a2,1a2,2 definierte Orientierung der mindestens einen zweiten elektrooptisch aktiven Schicht (2a,2b,2c,2d) relativ zu dem Lichtweg (5) und dem elektrischen Feld E derart gewählt sind, dass die Beeinflussung der Phase und/oder des Polarisationszustandes des Lichtes (5) in der ersten Schicht (1a,1b,1c,1d) der Beeinflussung der Phase und/oder des Polarisationszustandes des Lichtes (5) in der zweiten Schicht (2a,2b,2c,2d) entgegenwirkend ist. - Spannungssensor gemäss Anspruch 1, wobei mittels der Veränderungen der Brechungsindices ni,1 für einen sich entlang des Lichtweges (5) ausbreitenden Lichtstrahl (5) eine Halbwellenspannung Vπ des Spannungssensors definierbar ist, dadurch gekennzeichnet, dass die durch die Achsen der Doppelbrechung a1,1,a1,2 definierte Orientierung der mindestens einen ersten elektrooptisch aktiven Schicht (1a,1b,1c,1d) relativ zu dem Lichtweg (5) und dem elektrischen Feld E und die durch die Achsen der Doppelbrechung a2,1,a2,2 definierte Orientierung der mindestens einen zweiten elektrooptisch aktiven Schicht (2a,2b,2c,2d) relativ zu dem Lichtweg (5) und dem elektrischen Feld E derart gewählt sind, dass die Halbwellenspannung Vπ des Sensors grösser ist als bei einem gleichartigen Sensor, der statt der mindestens einen zweiten elektrooptisch aktiven Schicht (2a,2b,2c,2d) mindestens eine Vergleichsschicht aufweist, die nicht elektrooptisch aktiv, aber ansonsten der mindestens einen zweiten elektrooptisch aktiven Schicht (2a,2b,2c,2d) gleichartig ist.
- Spannungssensor gemäss einem der vorangegangenen Ansprüche, dadurch gekennzeichnet, dassdie durch die Achsen der Doppelbrechung a1,1,a1,2 definierte Orientierung der mindestens einen ersten elektrooptisch aktiven Schicht (1a,1b,1c,1d) relativ zu dem Lichtweg (5) und dem elektrischen Feld E unddie durch die Achsen der Doppelbrechung a2,1,a2,2 definierte Orientierung der mindestens einen zweiten elektrooptisch aktiven Schicht (2a,2b,2c,2d) relativ zu dem Lichtweg (5) und dem elektrischen Feld E, unddie Materialien der zwischen den Elektroden (3,4) angeordneten Schichten (1a,1b,1c,1d; 2a,2b,2c,2d) undderen effektive Schichtdicken derart gewählt sind, dass die Beeinflussung der Phase und/oder des Polarisationszustandes des Lichtes (5) in der ersten Schicht (1a,1b,1c,1d) die Beeinflussung der Phase und/oder des Polarisationszustandes des Lichtes (5) in der zweiten Schicht (2a,2b,2c,2d) teilweise kompensiert.
- Spannungssensor gemäss einem der vorangegangenen Ansprüche, dadurch gekennzeichnet, dass die erste Schicht (1a,1b,1c,1d) und die zweite Schicht (2a,2b,2c,2d) dieselbe Kristallsymmetrie aufweisen, und dass die Schichten (1a,1b,1c,1d; 2a,2b,2c,2d) derart angeordnet sind, dass die kristalline Orientierung der zweiten Schicht (2a,2b,2c,2d) sich aus der kristallinen Orientierung der ersten Schicht (1a,1b,1c,1d) durch eine Drehung der ersten Schicht (1a,1b,1c,1d) um 180° um eine der Achsen der Doppelbrechung a1,1 oder a1,2 ergibt.
- Spannungssensor gemäss einem der vorangegangenen Ansprüche, dadurch gekennzeichnet, dass die erste elektrooptisch aktive Schicht (1a,1b,1c,1d) aus demselben Material besteht wie die zweite elektrooptisch aktive Schicht (2a,2b,2c,2d).
- Spannungssensor gemäss den Ansprüchen 4 und 5, dadurch gekennzeichnet, dass die mindestens eine erste elektrooptisch aktive Schicht (1a,1b,1c,1d) mit einer effektiven Schichtdicke δ1 und die mindestens eine zweite elektrooptisch aktive Schicht (2a,2b,2c,2d) mit einer effektiven Schichtdicke δ2 zwischen den zwei Elektroden (3,4) angeordnet sind, wobei δ1≠ δ2 gilt.
- Spannungssensor gemäss einem der vorangegangenen Ansprüche, dadurch gekennzeichnet, dass eine Mehrzahl paarweise angeordneter erster und zweiter elektrooptisch aktiver Schichten (1a,1b,1c,1d; 2a,2b,2c,2d) zwischen den Elektroden (3,4) entlang des Lichtweges (5) angeordnet ist.
- Spannungssensor gemäss Anspruch 7, dadurch gekennzeichnet, dass die Mehrzahl paarweise angeordneter erster und zweiter elektrooptisch aktiver Schichten (1a,1b,1c,1d; 2a,2b,2c,2d) zwischen den Elektroden (3,4) derart angeordnet ist, dass eine Abweichung der mittels des Spannungssensors bestimmten Spannung von der zu messenden Spannung V minimal ist.
- Spannungssensor gemäss einem der vorangegangenen Ansprüche, dadurch gekennzeichnet, dass die mindestens eine erste elektrooptisch aktive Schicht (1a,1b,1c,1d) und die mindestens eine zweite elektrooptisch aktive Schicht (2a,2b,2c,2d) oder die Mehrzahl paarweise angeordneter erster und zweiter elektrooptisch aktiver Schichten (1a,1b,1c,1d; 2a,2b,2c,2d) stapelförmig zwischen den Elektroden (3,4) angeordnet sind, wobei die erste Schicht (1a) und die letzte Schicht (2a;2c;2d) in dem Stapel mit je einer der zwei Elektroden (3,4) in Kontakt ist, insbesondere wobei der Stapel im wesentlichen zylindrisch ausgestaltet ist.
- Spannungssensor gemäss einem der vorangegangenen Ansprüche, dadurch gekennzeichnet, dass die Phase und/oder der Polarisationszustand des Lichtes (5) nach Austritt aus der zweiten elektrooptisch aktiven Schicht (2a,2b,2c,2d) detektierbar ist, wobei aus der detektierten Phase und/oder dem detektierten Polarisationszustand ein Spannungssignal bestimmbar ist, wobei die Materialien von zwischen den Elektroden (3,4) angeordneten Schichten (1a,1b,1c,1d; 2a,2b,2c,2d) und deren effektive Schichtdicken derart gewählt sind, dass Einflüsse der Temperatur auf die detektierte Phase und/oder den detektierten Polarisationszustand im wesentlichen kompensiert sind.
- Spannungssensor gemäss einem der vorangegangenen Ansprüche, dadurch gekennzeichnet, dass zwischen den Elektroden (3,4) mindestens eine Abstandsschicht aus einem nicht elektrooptisch aktiven Material angeordnet ist.
- Spannungssensor gemäss einem der vorangegangenen Ansprüche, dadurch gekennzeichnet, dass die mindestens eine erste elektrooptisch aktive Schicht (1a,1b,1c,1d) kristallines BGO ist, das mit seiner [001]-Richtung im wesentlichen entlang der einer durch den Abstand der zwei Elektroden definierten Koordinate verläuft, und dass die mindestens eine zweite elektrooptisch aktive Schicht (2a,2b,2c,2d) kristallines BGO ist, dessen [001]-Richtung der [001]-Richtung der mindestens einen ersten elektrooptisch aktiven Schicht (1a,1b,1c,1d) im wesentlichen entgegengesetzt orientiert ist, und wobei die [110]-Richtungen der mindestens zwei Schichten (1a,1b,1c,1d; 2a,2b,2c,2d) im wesentlichen parallel oder antiparallel zueinander ausgerichtet sind, und insbesondere wobei der Lichtweg (5) in der mindestens einen ersten elektrooptisch aktiven Schicht (1a,1b,1c,1d) und in der mindestens einen zweiten elektrooptisch aktiven Schicht (2a,2b,2c,2d) im wesentlichen entlang einer dieser [001]-Richtungen verläuft.
- Spannungssensor gemäss einem der vorangegangenen Ansprüche, dadurch gekennzeichnet, dass mindestens die Elektroden (3,4) mitsamt der mindestens einen ersten elektrooptisch aktiven Schicht (1a,1b,1c,1d) und der mindestens einen zweiten elektrooptisch aktiven Schicht (2a,2b,2c,2d) mit Silikon (15) ummantelt sind.
- Verfahren zur Messung einer elektrischen Spannung V, wobei die Spannung V zwischen zwei voneinander beanstandet angeordneten Elektroden (3,4) anliegt und ein elektrisches Feld E erzeugt, wobei zwischen den Elektroden (3,4) mindestens eine erste elektrooptisch aktive Schicht (1a,1b,1c,1d) angeordnet wird, welche von einem Lichtstrahl (5) durchlaufen wird, dessen Phase und/oder Polarisationszustand durch das elektrische Feld E in der ersten Schicht (1a,1b,1c,1d) beeinflusst wird, und wobei zwischen den Elektroden (3,4) mindestens eine zweite elektrooptisch aktive Schicht (2a,2b,2c,2d) angeordnet wird, welche von dem Lichtstrahl (5) durchlaufen wird, dessen Phase und/oder Polarisationszustand durch das elektrische Feld E in der zweiten Schicht (2a,2b,2c,2d) beeinflusst wird,
dadurch gekennzeichnet, dass
die von dem Lichtstrahl (5) in der mindestens einen ersten Schicht (1a,1b,1c,1d) erfahrene Beeinflussung von der von dem Lichtstrahl (5) in der mindestens einen zweiten Schicht (2a,2b,2c,2d) erfahrenen Beeinflussung teilweise aufgehoben wird.
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
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EP03405271A EP1462811A1 (de) | 2003-03-28 | 2003-04-16 | Elektrooptischer Spannungssensor für hohe Spannungen |
US10/805,517 US6876188B2 (en) | 2003-03-28 | 2004-03-22 | Electro-optical voltage sensor for high voltages |
PCT/CH2004/000183 WO2004086064A1 (de) | 2003-03-28 | 2004-03-25 | Elektrooptischer spannungssensor |
CNB2004100314005A CN100374867C (zh) | 2003-03-28 | 2004-03-29 | 用于高压电的电光电压传感器 |
Applications Claiming Priority (3)
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EP03405213 | 2003-03-28 | ||
EP03405213.4A EP1462810B1 (de) | 2003-03-28 | 2003-03-28 | Temperaturkompensierter elektrooptischer Spannungssensor |
EP03405271A EP1462811A1 (de) | 2003-03-28 | 2003-04-16 | Elektrooptischer Spannungssensor für hohe Spannungen |
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EP1462811A1 true EP1462811A1 (de) | 2004-09-29 |
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EP03405271A Withdrawn EP1462811A1 (de) | 2003-03-28 | 2003-04-16 | Elektrooptischer Spannungssensor für hohe Spannungen |
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US (1) | US6876188B2 (de) |
EP (1) | EP1462811A1 (de) |
CN (1) | CN100374867C (de) |
WO (1) | WO2004086064A1 (de) |
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CN100399048C (zh) * | 2005-04-25 | 2008-07-02 | 中国科学院计算技术研究所 | 变换线性调频尺度成像算法因子的可复用计算方法及装置 |
JP4231038B2 (ja) * | 2005-08-22 | 2009-02-25 | 株式会社ケーヒン | 高電圧測定装置 |
WO2008077256A1 (en) * | 2006-12-22 | 2008-07-03 | Abb Research Ltd | Optical high voltage sensor |
CN101408558B (zh) * | 2008-09-10 | 2011-07-06 | 湾世伟 | 微型光学直流交流电场传感器 |
WO2011154029A1 (en) | 2010-06-07 | 2011-12-15 | Abb Research Ltd | High-voltage sensor with axially overlapping electrodes |
US8791831B2 (en) | 2011-09-23 | 2014-07-29 | Eaton Corporation | System including an indicator responsive to an electret for a power bus |
US9093867B2 (en) | 2011-09-23 | 2015-07-28 | Eaton Corporation | Power system including an electret for a power bus |
KR101996658B1 (ko) * | 2013-06-19 | 2019-07-04 | 엘지디스플레이 주식회사 | 입체영상표시장치와 이의 구동방법 |
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Also Published As
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US6876188B2 (en) | 2005-04-05 |
WO2004086064A1 (de) | 2004-10-07 |
US20040189278A1 (en) | 2004-09-30 |
CN1534301A (zh) | 2004-10-06 |
CN100374867C (zh) | 2008-03-12 |
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